dcc.Location unable to handle path separator '/'

Describe your context
Please provide us your environment, so we can easily reproduce the issue.

• replace the result of pip list | grep dash below

dash                      2.8.1
dash-ag-grid              2.0.0a1
dash-bootstrap-components 1.3.1
dash-core-components      2.0.0
dash-daq                  0.5.0
dash-html-components      2.0.0
dash-table                5.0.0

• if frontend related, tell us your Browser, Version and OS

Bug exists in all browsers I have.

Describe the bug

I have the following code:

@callback(
        Output('url-output', 'pathname'), 
        [Input('tabs', 'active_tab'), Input('site-table', 'selectionChanged')],
        prevent_initial_call=True)
def url_manger(tab_id, site_selection):
    path = tab_id
    if site_selection:
        path += '/' + site_selection[0]['Site_id']
    return path

When site selection is activated, the new url is appended to the tab section of existing path: "site_tab/:site_id:" -> "site_tab/site_tab/:site_id:"; if tab is activated instead (site_selection = None), things work as expected.

If I change the delimiter from '/' slash to any other character, for example such as '_' lower dash, things work as expected; nothing gets appended to the path but the path is exactly the same as the return value.

Expected behavior

I think I should be able to use '/' in the Output value for dcc.Location.pathname? If I can not, how should I delimit paths or what should I do? The documentation says nothing about this. As far as I know there is no way to attach dcc.Link to the values of components so I wouldn't depend on using the callbacks?

I use quite basic Dash setup with stylesheets and Redis cache. I do not use Page Registry, because I am refactoring someone else's code from tab-oriented single-page app towards url-stateful multi-page app. I am trying to do this without Page Registry as Page Registry would demand more refactoring. Everything works if I use '_' lower dash as "path separator"; it just looks silly.

Screenshots

N/A

Start at dcc.Location pathname handling and the callback that returns a slash-delimited path; reproduce the site_tab/site_id case described in the issue. Compare the browser URL with the callback's returned value, and verify that tab-only paths remain unchanged while slash-separated paths are handled correctly.